#if HAVE_CONFIG_H
    #include <config.h>
#endif

#include <stdlib.h>     /* for malloc() */
#include <string.h>     /* for memcpy() */

#include "private/md5.h"
#include "share/alloc.h"

#ifndef FLaC__INLINE
    #define FLaC__INLINE
#endif

/*
 * This code implements the MD5 message-digest algorithm.
 * The algorithm is due to Ron Rivest.  This code was
 * written by Colin Plumb in 1993, no copyright is claimed.
 * This code is in the public domain; do with it what you wish.
 *
 * Equivalent code is available from RSA Data Security, Inc.
 * This code has been tested against that, and is equivalent,
 * except that you don't need to include two pages of legalese
 * with every copy.
 *
 * To compute the message digest of a chunk of bytes, declare an
 * MD5Context structure, pass it to MD5Init, call MD5Update as
 * needed on buffers full of bytes, and then call MD5Final, which
 * will fill a supplied 16-byte array with the digest.
 *
 * Changed so as no longer to depend on Colin Plumb's `usual.h' header
 * definitions; now uses stuff from dpkg's config.h.
 *  - Ian Jackson <ijackson@nyx.cs.du.edu>.
 * Still in the public domain.
 *
 * Josh Coalson: made some changes to integrate with libFLAC.
 * Still in the public domain.
 */

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, in, s) \
    (w += f(x, y, z) + in, w = (w << s | w >> (32 - s)) + x)

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
static void FLAC__MD5Transform(FLAC__uint32 buf[4], FLAC__uint32 const in[16])
{
    register FLAC__uint32 a, b, c, d;

    a = buf[0];
    b = buf[1];
    c = buf[2];
    d = buf[3];

    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

    buf[0] += a;
    buf[1] += b;
    buf[2] += c;
    buf[3] += d;
}

#if WORDS_BIGENDIAN
static void byteSwap(FLAC__uint32* buf, unsigned words)
{
    register FLAC__uint32 x;
    do
    {
        x = *buf;
        x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff);
        *buf++ = (x >> 16) | (x << 16);
    }
    while (--words);
}
static void byteSwapX16(FLAC__uint32* buf)
{
    register FLAC__uint32 x;

    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
    x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf = (x >> 16) | (x << 16);
}
#else
    #define byteSwap(buf, words)
    #define byteSwapX16(buf)
#endif

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
static void FLAC__MD5Update(FLAC__MD5Context* ctx, FLAC__byte const* buf, unsigned len)
{
    FLAC__uint32 t;

    /* Update byte count */

    t = ctx->bytes[0];
    if ((ctx->bytes[0] = t + len) < t)
        ctx->bytes[1]++;    /* Carry from low to high */

    t = 64 - (t & 0x3f);    /* Space available in ctx->in (at least 1) */
    if (t > len)
    {
        memcpy((FLAC__byte*)ctx->in + 64 - t, buf, len);
        return;
    }
    /* First chunk is an odd size */
    memcpy((FLAC__byte*)ctx->in + 64 - t, buf, t);
    byteSwapX16(ctx->in);
    FLAC__MD5Transform(ctx->buf, ctx->in);
    buf += t;
    len -= t;

    /* Process data in 64-byte chunks */
    while (len >= 64)
    {
        memcpy(ctx->in, buf, 64);
        byteSwapX16(ctx->in);
        FLAC__MD5Transform(ctx->buf, ctx->in);
        buf += 64;
        len -= 64;
    }

    /* Handle any remaining bytes of data. */
    memcpy(ctx->in, buf, len);
}

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void FLAC__MD5Init(FLAC__MD5Context* ctx)
{
    ctx->buf[0] = 0x67452301;
    ctx->buf[1] = 0xefcdab89;
    ctx->buf[2] = 0x98badcfe;
    ctx->buf[3] = 0x10325476;

    ctx->bytes[0] = 0;
    ctx->bytes[1] = 0;

    ctx->internal_buf = 0;
    ctx->capacity = 0;
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
void FLAC__MD5Final(FLAC__byte digest[16], FLAC__MD5Context* ctx)
{
    int count = ctx->bytes[0] & 0x3f;   /* Number of bytes in ctx->in */
    FLAC__byte* p = (FLAC__byte*)ctx->in + count;

    /* Set the first char of padding to 0x80.  There is always room. */
    *p++ = 0x80;

    /* Bytes of padding needed to make 56 bytes (-8..55) */
    count = 56 - 1 - count;

    if (count < 0)      /* Padding forces an extra block */
    {
        memset(p, 0, count + 8);
        byteSwapX16(ctx->in);
        FLAC__MD5Transform(ctx->buf, ctx->in);
        p = (FLAC__byte*)ctx->in;
        count = 56;
    }
    memset(p, 0, count);
    byteSwap(ctx->in, 14);

    /* Append length in bits and transform */
    ctx->in[14] = ctx->bytes[0] << 3;
    ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
    FLAC__MD5Transform(ctx->buf, ctx->in);

    byteSwap(ctx->buf, 4);
    memcpy(digest, ctx->buf, 16);
    memset(ctx, 0, sizeof(ctx));    /* In case it's sensitive */
    if (0 != ctx->internal_buf)
    {
        free(ctx->internal_buf);
        ctx->internal_buf = 0;
        ctx->capacity = 0;
    }
}

/*
 * Convert the incoming audio signal to a byte stream
 */
static void format_input_(FLAC__byte* buf, const FLAC__int32* const signal[], unsigned channels, unsigned samples, unsigned bytes_per_sample)
{
    unsigned channel, sample;
    register FLAC__int32 a_word;
    register FLAC__byte* buf_ = buf;

    #if WORDS_BIGENDIAN
    #else
    if (channels == 2 && bytes_per_sample == 2)
    {
        FLAC__int16* buf1_ = ((FLAC__int16*)buf_) + 1;
        memcpy(buf_, signal[0], sizeof(FLAC__int32) * samples);
        for (sample = 0; sample < samples; sample++, buf1_ += 2)
            *buf1_ = (FLAC__int16)signal[1][sample];
    }
    else if (channels == 1 && bytes_per_sample == 2)
    {
        FLAC__int16* buf1_ = (FLAC__int16*)buf_;
        for (sample = 0; sample < samples; sample++)
            *buf1_++ = (FLAC__int16)signal[0][sample];
    }
    else
    #endif
    if (bytes_per_sample == 2)
    {
        if (channels == 2)
        {
            for (sample = 0; sample < samples; sample++)
            {
                a_word = signal[0][sample];
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word;
                a_word = signal[1][sample];
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word;
            }
        }
        else if (channels == 1)
        {
            for (sample = 0; sample < samples; sample++)
            {
                a_word = signal[0][sample];
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word;
            }
        }
        else
        {
            for (sample = 0; sample < samples; sample++)
            {
                for (channel = 0; channel < channels; channel++)
                {
                    a_word = signal[channel][sample];
                    *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                    *buf_++ = (FLAC__byte)a_word;
                }
            }
        }
    }
    else if (bytes_per_sample == 3)
    {
        if (channels == 2)
        {
            for (sample = 0; sample < samples; sample++)
            {
                a_word = signal[0][sample];
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word;
                a_word = signal[1][sample];
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word;
            }
        }
        else if (channels == 1)
        {
            for (sample = 0; sample < samples; sample++)
            {
                a_word = signal[0][sample];
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word;
            }
        }
        else
        {
            for (sample = 0; sample < samples; sample++)
            {
                for (channel = 0; channel < channels; channel++)
                {
                    a_word = signal[channel][sample];
                    *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                    *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                    *buf_++ = (FLAC__byte)a_word;
                }
            }
        }
    }
    else if (bytes_per_sample == 1)
    {
        if (channels == 2)
        {
            for (sample = 0; sample < samples; sample++)
            {
                a_word = signal[0][sample];
                *buf_++ = (FLAC__byte)a_word;
                a_word = signal[1][sample];
                *buf_++ = (FLAC__byte)a_word;
            }
        }
        else if (channels == 1)
        {
            for (sample = 0; sample < samples; sample++)
            {
                a_word = signal[0][sample];
                *buf_++ = (FLAC__byte)a_word;
            }
        }
        else
        {
            for (sample = 0; sample < samples; sample++)
            {
                for (channel = 0; channel < channels; channel++)
                {
                    a_word = signal[channel][sample];
                    *buf_++ = (FLAC__byte)a_word;
                }
            }
        }
    }
    else   /* bytes_per_sample == 4, maybe optimize more later */
    {
        for (sample = 0; sample < samples; sample++)
        {
            for (channel = 0; channel < channels; channel++)
            {
                a_word = signal[channel][sample];
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word; a_word >>= 8;
                *buf_++ = (FLAC__byte)a_word;
            }
        }
    }
}

/*
 * Convert the incoming audio signal to a byte stream and FLAC__MD5Update it.
 */
FLAC__bool FLAC__MD5Accumulate(FLAC__MD5Context* ctx, const FLAC__int32* const signal[], unsigned channels, unsigned samples, unsigned bytes_per_sample)
{
    const size_t bytes_needed = (size_t)channels * (size_t)samples * (size_t)bytes_per_sample;

    /* overflow check */
    if ((size_t)channels > SIZE_MAX / (size_t)bytes_per_sample)
        return false;
    if ((size_t)channels * (size_t)bytes_per_sample > SIZE_MAX / (size_t)samples)
        return false;

    if (ctx->capacity < bytes_needed)
    {
        FLAC__byte* tmp = (FLAC__byte*)realloc(ctx->internal_buf, bytes_needed);
        if (0 == tmp)
        {
            free(ctx->internal_buf);
            if (0 == (ctx->internal_buf = (FLAC__byte*)safe_malloc_(bytes_needed)))
                return false;
        }
        ctx->internal_buf = tmp;
        ctx->capacity = bytes_needed;
    }

    format_input_(ctx->internal_buf, signal, channels, samples, bytes_per_sample);

    FLAC__MD5Update(ctx, ctx->internal_buf, bytes_needed);

    return true;
}